Predicting Postoperative Complications and Mortality After Acetabular Surgery in the Elderly

A Comparison of Risk Stratification Models

Chang-Yeon Kim, MD; Nikunj N. Trivedi, MD; Lakshmanan Sivasundaram, MD; George Ochenjele, MD; Raymond W. Liu, MD; Heather Vallier, MD


Curr Orthop Pract. 2020;31(2):162-167. 

In This Article

Abstract and Introduction


Background: Geriatric acetabular fractures are becoming increasingly common. Surgeons must balance the long-term benefits of surgery with the risk of postoperative complications. Several risk stratification models have been adapted to assist surgeons with this decision-making. We compared the accuracy of the Elixhauser Comorbidity Measure (ECM), the Charlson Comorbidity Index (CCI), and the Combined Comorbidity Score (CCS) for predicting adverse events and postoperative discharge destination after surgical treatment of geriatric patients with acetabular fractures.

Methods: A search of the National Inpatient Sample for patients over the age of 65 yr who had fixation of an acetabular fracture between 2002 and 2014 was undertaken. Logistic regression models of basic demographic variables and the ECM, CCI, or the CCS were used to predict inpatient mortality, complications, extended length of stay, and discharge disposition. The predictive discrimination of each model was evaluated using the C-statistic.

Results: A total of 2,497 patients were identified. The model using demographic variables and the CCS outperformed the corresponding ECM and CCI models, with an area under the curve (AUC) of 0.829 for mortality (compared to 0.791 and 0.689, respectively), 0.791 for cardiac complications (compared to 0.694 and 0.704, respectively), 0.789 for renal complications (compared to 0.787 and 0.683, respectively), and 0.760 for pulmonary complications (compared to 0.750 and 0.662, respectively).

Conclusions: The CCS was the best predictive model for assessing postoperative complications, followed by the ECM then CCI. Our results may assist in preoperative decision-making for geriatric patients with acetabular fractures.

Level of Evidence: Level III.


With a 2.4-fold increase in the past 4 decades, fractures in geriatric patients are becoming increasingly common.[1,2] Open reduction and internal fixation remains the gold-standard treatment for displaced acetabular fractures in young patients. However, elderly patients often have medical conditions that put them at risk for postoperative morbidity and mortality.[3,4] Along with mechanisms of injury, hip congruency, and femoral head considerations, advanced age and its associated comorbidities are significant factors in the decision to treat these patients operatively or nonoperatively. When deciding which patients are best suited for surgery, surgeons must balance the risk of postoperative complications with the surgery's potential for long-term functional improvements.

The Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Index (ECM), and Combined Comorbidity Score (CCS) are risk stratification models that have been adapted to assist surgeons with this decision-making.[5,6] The ECM includes 30 comorbidities, and the CCI includes 17 comorbidities (Table 1A). Although the CCI is more widely used by orthopaedic surgeons, the ECM has been shown to be more predictive of mortality and adverse events after hip and proximal humeral fracture surgery.[7,8] Recently, the Combined Comorbidity Score (CCS), an index that combines the ECM and CCI variables, has been developed and validated (Table 1B).[9] Currently, none of these indices have been validated for geriatric patients undergoing operative fixation of acetabular fractures.

The purpose of this study was to compare the accuracy of the ECM, CCI, and the recently developed CCS for predicting adverse events after operative fixation of acetabular fractures in geriatric patients. We hypothesized that the CCS with base demographics would be the most accurate of our models.